Cancer-related fatigue and chemo fatigue: what helps

Cancer-related fatigue is exhaustion caused by cancer or its treatment that does not usually go away with sleep or rest. Research suggests it affects almost 65 in every 100 people with cancer [2]. For most people it eases after treatment ends, but for some it lasts months or even years [1]. Regular moderate exercise, built up gradually, is one of the best-evidenced ways to reduce it [1][6]. Fatigue support is one part of cancer rehabilitation in the UK.

What is cancer-related fatigue, and what does chemo fatigue feel like?

Cancer-related fatigue means feeling very tired, exhausted and lacking energy because of the cancer or its treatment. Unlike ordinary tiredness, it "doesn't usually go away with sleep or rest" [2]. Macmillan describes people who "may get tired more quickly after less activity and feel exhausted even if they are getting enough rest and sleep" [1].

Cancer Research UK and Macmillan list these common signs [1][2]:

• lack of energy and needing to rest after small amounts of activity
• difficulty concentrating or remembering things
• feeling breathless after small tasks, such as having a shower or making the bed
• aching muscles and weakness
• sleeping badly, or sleeping a lot and still feeling tired
• feeling dizzy or light-headed
• mood changes, feeling more emotional or low

Everyday jobs such as getting dressed can feel like a big effort, and fatigue can affect work and relationships [1]. It is real and common, not a sign that you are not coping. Your team may ask you to score it from 0 to 10 [1], and keeping your own score helps you describe it.

Why does cancer cause fatigue?

Fatigue can come from the cancer itself, from treatment, and from knock-on problems such as anaemia, poor sleep, pain, eating difficulties and low mood [1][3]. Several are treatable, so tell your team.

• Chemotherapy. Most chemotherapy drugs affect your red blood cells, so levels drop between treatments. Depending on the type of chemotherapy, they usually start to recover within 2 weeks [3]. Sickness, diarrhoea and dehydration add to the tiredness [3].
• Radiotherapy. "Most people having radiotherapy feel increasingly fatigued as they go through their treatment" [3].
• Hormone therapy. It blocks or lowers hormones in the body, which can cause fatigue [3].
• Surgery. Fatigue afterwards usually gets better with time, over a few weeks or months [3].
• Targeted drugs and immunotherapy. General tiredness is a listed side effect [3].
• Anaemia. Too few red blood cells means less oxygen reaches your body, and you may also feel breathless, dizzy and light-headed [1][3].
• Sleep, pain, food and mood. Poor sleep, pain and not getting enough food all add to fatigue, and "anxiety, depression, stress and tension can make fatigue worse" [1].
• Other medicines. Painkillers, anti-sickness drugs, steroids and sleeping tablets can all make you drowsy [3].

How long does chemo fatigue last?

For most people fatigue gets better after treatment finishes, but for some it continues for months or sometimes years [1]. Cancer Research UK says it can last "several weeks, months, or even years after treatment" [2]. Does chemo fatigue go away? Usually it improves, but there is no fixed timetable.

Some people still have chemo fatigue years later. Macmillan's advice is that "it is important to tell a member of your healthcare team if you have fatigue at any time" [1]. Our guide to exercise after cancer treatment covers rebuilding once treatment ends.

Does fatigue get worse with each chemo treatment?

It can. A multi-centre study followed 249 people having chemotherapy. In the two weeks after each cycle, fatigue was a fairly constant presence, and "fatigue experiences increase over consecutive cycles of chemotherapy" [5]. It was an observational study, so it shows a common pattern, not what will happen to you.

Most chemotherapy drugs lower your red blood cell levels between treatments [3], and anaemia can add to tiredness [1]. If each cycle leaves you noticeably more exhausted, tell your team: anaemia can be treated, sometimes with a blood transfusion [4]. Our guide to exercise during chemotherapy covers adjusting exercise around your cycles and blood counts.

Does exercise help cancer-related fatigue?

Yes. Exercise is one of the best-evidenced treatments for cancer-related fatigue, during and after treatment [6][7].

The 2017 meta-analysis. Researchers pooled 113 studies with 11,525 participants. Exercise (weighted effect size 0.30), psychological interventions (0.27) and the two combined (0.26) all reduced fatigue. Medicines had the smallest effect (0.09, a borderline result), and the authors concluded exercise and psychological approaches "are significantly better than the available pharmaceutical options" [6].

A 2012 Cochrane review. In 38 pooled comparisons (2,648 people) from 56 studies, exercise reduced fatigue more than control groups [7]. The authors concluded aerobic exercise "can be regarded as beneficial for individuals with cancer-related fatigue during and post-cancer therapy, specifically those with solid tumours" [7].

International guidelines. The 2019 ACSM roundtable lists fatigue among the outcomes exercise improves [8], and the 2022 ASCO guideline found exercise during treatment improved fitness, strength and fatigue [9]. Macmillan agrees: "there is good evidence that physical activity, such as walking quickly, is one of the best ways to help reduce symptoms of fatigue" [1].

The effects are modest on average. Exercise is not a cure, but it is one of the best-supported things you can do yourself. See exercise and cancer for the wider benefits.

The exercise guidelines for cancer-related fatigue. For programmes lasting at least 12 weeks, moderate-intensity aerobic exercise three times a week, in sessions of about 30 minutes, "can significantly reduce cancer-related fatigue both during and after treatment" [8]. Twice-weekly moderate strength training may also help, and combining the two is another option [8].

That is a target to build towards, not a starting point. Cancer Research UK suggests you "start with short chunks (10 to 15 minutes) of gentle activity. Then, gradually build up until you reach your target" [11]. Macmillan puts it simply: "Doing something is better than doing nothing. It is important to listen to your body and do what you feel able to do" [10].

During treatment, do not exercise if you feel unwell or have any symptoms that worry you [14]. If you have a high temperature, call your team straight away rather than exercising [12][15]. If your blood counts are low, ask what is safe: with low white blood cells you may be advised to avoid busy public places, including public gyms, and with low platelets to exercise gently and avoid high-impact activities [11][14]. If cancer has spread to your bones or you have bone thinning, you have a central or PICC line, or you are anaemic, ask your team what is safe before you start: with bone problems it is usually best to avoid high-impact activities and repeated bending forward at the waist, such as sit-ups; with a line, avoid swimming and vigorous upper-body exercise; and with anaemia, listen to your body and rest when you need to until it improves [14].

How do you start exercising when you are exhausted?

Start smaller than you think you need to, and balance activity with rest. Macmillan's advice is to "pace yourself, take short naps and rests but try to balance them with some activity or exercise" [1]. These steps come from Macmillan and Cancer Research UK:

• Keep a fatigue diary. Note when your energy is best and worst. "If you have fatigue, planning ahead can help" [1].
• Put the day in order. List what you want to do in order of importance [4], and fit a short walk into your best hours.
• Build up slowly. Add a few minutes at a time, not a whole new session.
• Keep a normal sleep routine [1], going to bed and getting up at the same time each day [4].
• Eat as well as you can. Not getting enough food leaves you more tired [1]. See our guide to nutrition during cancer treatment.
• Look after your mood. Cancer Research UK describes cognitive behavioural therapy (CBT) [4], and psychological support reduced fatigue about as much as exercise in the 2017 meta-analysis [6].
• Ask about an occupational therapist. "Your GP or cancer doctor may refer you to an occupational therapist. They can advise you on how to pace yourself and manage tiredness" [10].

When should you call your care team about fatigue?

Tell your team about fatigue at any point in treatment or afterwards. Use the 24-hour number your chemotherapy unit or hospital gave you [15]. The NHS says to call your care team now if you have [12]:

• a high temperature: feeling hot, cold, sweaty or shivery, or the skin on your back or chest feeling hotter than usual
• other signs of an infection, such as a sore throat, cough, diarrhoea, peeing a lot or pain when peeing
• throbbing or cramping pain, swelling and warmth in a leg or arm
• sudden breathlessness, sharp chest pain (may be worse when you breathe in) and a cough or coughing up blood

Chemo fatigue and breathlessness. Feeling breathless after small tasks can be part of cancer-related fatigue [2]. But it can also be a sign of anaemia, alongside a lack of energy and noticeable heartbeats (palpitations) [12], or dizziness and chest tightness [1]. Do not assume breathlessness is "just fatigue". Tell your team, and use the urgent list above if it comes on suddenly.

Who can help with cancer-related fatigue?

Your cancer nurse specialist, oncologist or GP is the place to start. They can look for treatable causes such as anaemia, pain or poor sleep, and refer you to other professionals [1][4].

• Occupational therapist, for pacing and managing everyday tasks [10].
• Dietitian, if eating problems or weight loss are adding to fatigue [1].
• Counsellor or psychological support, for anxiety and low mood [1][4].
• Clinical exercise physiologist. Macmillan describes a clinical exercise physiologist as "an expert in screening, assessing and advising what physical activity is best for you and your situation" [10]. They "prescribe and deliver a range of exercise programmes tailored to the patient's needs" and work in areas including oncology [13], building a plan around the energy you actually have.

Our guide to the cancer rehabilitation team explains who does what.

Talk to your oncology team first

Fatigue can have causes that need medical treatment, so speak to your doctor, specialist nurse or GP before starting any new activity, especially if you have not been active for a long time [11]. Your team knows your treatment, blood counts and other conditions, and can tell you what is safe right now.

For one-to-one support building activity around your treatment and energy levels, request a match with a verified clinical exercise physiologist through The Health Nav. You can also email support@thehealthnav.co.uk.

This article is general information and does not replace advice from your own healthcare team.

References

1. Macmillan Cancer Support. Tiredness (fatigue) and cancer. https://www.macmillan.org.uk/cancer-information-and-support/impacts-of-cancer/tiredness (accessed 12 Oct 2026)
2. Cancer Research UK. What is cancer fatigue? https://www.cancerresearchuk.org/about-cancer/coping/physically/fatigue/what-is-cancer-fatigue (accessed 12 Oct 2026)
3. Cancer Research UK. Causes of cancer fatigue. https://www.cancerresearchuk.org/about-cancer/coping/physically/fatigue/causes (accessed 12 Oct 2026)
4. Cancer Research UK. Managing and treating cancer fatigue. https://www.cancerresearchuk.org/about-cancer/coping/physically/fatigue/managing-treating-cancer-fatigue (accessed 12 Oct 2026)
5. Miller M, Maguire R, Kearney N. Patterns of fatigue during a course of chemotherapy: results from a multi-centre study. European Journal of Oncology Nursing. 2007;11(2):126-132. https://doi.org/10.1016/j.ejon.2006.05.001
6. Mustian KM, Alfano CM, Heckler C, et al. Comparison of pharmaceutical, psychological, and exercise treatments for cancer-related fatigue: a meta-analysis. JAMA Oncology. 2017;3(7):961-968. https://doi.org/10.1001/jamaoncol.2016.6914
7. Cramp F, Byron-Daniel J. Exercise for the management of cancer-related fatigue in adults. Cochrane Database of Systematic Reviews. 2012;(11):CD006145. https://doi.org/10.1002/14651858.CD006145.pub3
8. Campbell KL, Winters-Stone KM, Wiskemann J, et al. Exercise guidelines for cancer survivors: consensus statement from international multidisciplinary roundtable. Medicine and Science in Sports and Exercise. 2019;51(11):2375-2390. https://doi.org/10.1249/MSS.0000000000002116
9. Ligibel JA, Bohlke K, May AM, et al. Exercise, diet, and weight management during cancer treatment: ASCO guideline. Journal of Clinical Oncology. 2022;40(22):2491-2507. https://doi.org/10.1200/JCO.22.00687
10. Macmillan Cancer Support. Physical activity and cancer. https://www.macmillan.org.uk/cancer-information-and-support/treatment/preparing-for-treatment/physical-activity-and-cancer (accessed 12 Oct 2026)
11. Cancer Research UK. Exercise and cancer. https://www.cancerresearchuk.org/about-cancer/coping/physically/exercise-guidelines (accessed 12 Oct 2026)
12. NHS. Chemotherapy: side effects. https://www.nhs.uk/conditions/chemotherapy/side-effects/ (accessed 12 Oct 2026)
13. NHS Health Careers. Clinical exercise physiologist. https://www.healthcareers.nhs.uk/explore-roles/healthcare-science/roles-healthcare-science/physiological-sciences/clinical-exercise-physiologist (accessed 12 Oct 2026)
14. Macmillan Cancer Support. Exercising safely when you have cancer. https://www.macmillan.org.uk/cancer-information-and-support/treatment/preparing-for-treatment/physical-activity-and-cancer/exercising-safely (accessed 12 Oct 2026)
15. Macmillan Cancer Support. Side effects of chemotherapy. https://www.macmillan.org.uk/cancer-information-and-support/treatment/types-of-treatment/chemotherapy/side-effects-of-chemotherapy (accessed 12 Oct 2026)